CRC

A cyclic redundancy check (CRC) is an error-detecting code.

http://en.wikipedia.org/wiki/Cyclic_redundancy_check

http://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks

http://www.drdobbs.com/implementing-the-ccitt-cyclical-redundan/199904926

http://www.ietf.org/rfc/rfc1952.txt

HDLC like framing

The http://www.ietf.org/rfc/rfc1662.txt has two examples of CRC calculations.

Polynom CRC-16: 0x8408 ( CRC-16-CCITT Reversed )

Polynom: x⁰ + x⁵ + x¹² + x¹⁶

CRC-16-IBM

Bisync, Modbus, USB, ANSI X3.28, SIA DC-07, many others; also known as CRC-16 and CRC-16-ANSI

Polynom: x¹⁶ + x¹⁵ + x² + 1